This invention relates generally to liquid dispensing apparatus, and more particularly, to a liquid dispenser which is operable automatically in response to an increase in ambient temperature to supply a quantity of a liquid reagent or chemical composition.
The periodic addition or injection of chemicals into a water or other liquid-circulating system to maintain a desired minimum concentration of the chemical is common practice in numerous industrial applications. By way of example, chemicals are injected into the water circulating and cooling towers of air conditioning systems to prevent the deposition of scale, the corrosion of the equipment, and/or the growth of algae and slime.
So-called "chemical treatment" in a given industry may consist in the addition of one or more liquid reagents to a body of water or other liquid, either on a more of less continuous basis, or on a periodic basis. In large installations, the treatment apparatus may be very sophisticated with metering pumps, electronic controls, automatically opening valves, etc., to maintain proper operating conditions. However, with smaller installations the sophisticated machinery and controls become prohibitively expensive and as a consequence simpler methods are used. Examples of the simpler devices are as follows:
1. An adjustable metering pump operating continuously; PA1 2. A metering pump with a timing device to vary the feed according to a preset cycle; PA1 3. Venturi devices; PA1 4. Porous containers of dry chemical deposited in a large storage reservoir designed to allow slow solution of the chemical.
Except for the fourth example, all of the above require precise plumbing fixtures and/or electrical controls and the maintenance and technical adjustment requirements are always a problem.